Despite the CDC's decision to end its emergency response to the H5N1 avian influenza outbreak, a significant drop in U.S. human cases may be masking a larger, ongoing threat. While some public health officials suggest the risk is low, new scientific studies and global case reports paint a more complex picture, showing the virus is evolving and continuing to spread to new hosts and regions. The recent "lull" in the outbreak, therefore, might not be a sign of the virus's retreat, but rather a temporary pause.
CDC Ends H5N1 Emergency Response As Human Cases Stall
On July 2nd, the CDC officially ended its emergency response to the H5N1 avian influenza outbreak, citing a significant drop in reported infections and no new U.S. human cases since February. The response, originally declared in April 2024, allowed for expanded public health resources and staffing. Going forward, bird flu surveillance and response will transition back to the agency’s influenza division. While the virus has infected over 175 million U.S. birds and spread to more than 1,000 cattle herds in 17 states, officials say serious public health risk remains low (Goodman & Owermohle, 2025).
Bird Flu Evolving Faster, Spreading Via Wild Birds And New Hosts
A new study published in Science Advances by Canadian scientists finds that H5N1 bird flu has continued to evolve rapidly since it was first detected, with successive reassortments producing increasingly fit viral lineages capable of infecting more species and spreading more widely. The researchers analyzed nearly 3,000 viral genomes from wild and domestic birds collected across Canada between 2021 and 2024. Their findings show that the virus is now primarily spreading via migratory wild birds—unlike past outbreaks that were centered in poultry—and that some mammals are transmitting the virus back to birds, an unusual spillback event. The Prairie Pothole Region in the Great Plains was identified as a major hotspot for viral mixing and transmission due to its dense migratory bird populations. The study highlights the virus’s ongoing adaptation and emphasizes the need for continued surveillance to anticipate future reassortments (Kasal, 2025).
Cornell Study Quantifies Economic Damage From Ohio Dairy Outbreak
A Cornell University study published this week in Nature Communications confirms and expands on findings previously reported, quantifying the financial toll of a spring 2024 H5N1 outbreak on a single Ohio dairy farm. The research found that the outbreak led to an estimated $737,500 loss due to decreased milk production and cow mortality. Researchers tracked 3,876 cows, of which 20% became infected following a herd transfer from Texas. Sick cows produced about 900 kg (1,984 pounds) less milk over a 60-day period, and when combined with cow loss, the total economic hit averaged $950 per infected animal. Sick cows also experienced a sixfold increase in mortality and were culled at over three times the rate of unaffected cows (Van Beusekom, 2025).
Cambodia Logs 12th Human H5N1 Case Of 2025; 9 Since Early June
Cambodia’s health ministry has confirmed a new human H5N1 infection in a 5-year-old boy from Kampot province, bringing the country’s total to 12 cases this year—including 9 since early June. The child had daily contact with a backyard flock of 40 chickens, some of which were reportedly sick or had died. Cambodian poultry continues to harbor a reassortant H5N1 strain combining an older local clade with elements of the globally circulating 2.3.4.4b clade, both associated with high severity and mortality in humans (Schnirring, 2025).
Bangladesh And India Report New H5N1 Cases To WHO
The World Health Organization has confirmed new human H5N1 infections in Bangladesh and India. Bangladesh’s case involves a child from Chittagong who developed fever, diarrhea, and respiratory symptoms after exposure to backyard poultry in May. The child has recovered, marking the country’s third H5N1 case of 2025. India reported a fatal case in a man from Karnataka, with limited exposure details available. Both infections are linked to the older 2.3.2.1a clade that continues to circulate in birds across the region (Schnirring, 2025).
Bird Flu Outbreak In India Prompts Culling Of Over 6,700 Birds In Odisha
Authorities in India have confirmed an H5N1 avian influenza outbreak at a poultry farm in Odisha’s Puri district, leading to the culling of more than 6,700 birds over the weekend. The outbreak was verified after samples from Bada Ankula village tested positive at the National Institute of High Security Animal Diseases. Five rapid response teams and health officials were deployed, and the movement of live birds in and out of the area has been fully restricted (The Economic times, 2025).
Scientific American: Where Did Bird Flu Go?
In a July 15th Scientific American article, journalist Meghan Bartels examined the apparent decline in bird flu reports and the risks of complacency. Experts interviewed—including epidemiologist Dr. Jennifer Nuzzo and virologist Dr. Angela Rasmussen—stressed that the H5N1 virus remains a serious threat, even if current case counts appear low. They attribute the recent lull in outbreaks largely to seasonal factors: higher summer temperatures and limited migratory bird activity have temporarily slowed transmission, particularly in poultry. However, they cautioned that infection rates have historically surged in the fall, and reduced testing across sectors may be masking undetected cases. As Rasmussen put it, “No news in my world is not good news.” (Bartels, 2025)
Waffle House Drops Egg Surcharge As Prices Fall
Waffle House has ended its 50-cent egg surcharge, which had been in place since February due to surging egg prices tied to the bird flu outbreak. The chain was one of several restaurants, including Denny’s, that added temporary surcharges (Scripps News Group, 2025).
Ultimately, the recent downturn in H5N1 cases in the U.S. seems to be a moment of relative calm, not the end of the storm. The cessation of the CDC's emergency response is a significant step, but it must be viewed in the context of the virus's continued global spread, rapid evolution, and established economic toll. As experts warn, the virus remains a serious and adaptable threat, and a return to seasonal peaks in the fall is a distinct possibility. Continued surveillance, both domestically and internationally, will be critical to anticipate and prepare for future outbreaks.
References
Bartels, M. (2025, July 15). Bird Flu Is out of the News but Still Circulating. Scientific American. https://www.scientificamerican.com/article/bird-flu-is-out-of-the-news-but-still-circulating/
Goodman, B., & Owermohle, S. (2025, July 7). CDC ends emergency response to H5N1 bird flu. CNN. https://www.cnn.com/2025/07/07/health/cdc-bird-flu-response
Kasal, K. (2025, July 10). Bird flu found to evolve rapidly, infecting more hosts and finding ways to spread more effectively. Medicalxpress.com; Medical Xpress. https://medicalxpress.com/news/2025-07-bird-flu-evolve-rapidly-infecting.html#google_vignette
Schnirring, L. (2025a, July 3). Center for Infectious Disease Research and Policy. Umn.edu. https://www.cidrap.umn.edu/avian-influenza-bird-flu/cambodia-confirms-12th-h5n1-avian-flu-infection-year
Schnirring, L. (2025b, July 15). Center for Infectious Disease Research and Policy. Umn.edu. https://www.cidrap.umn.edu/avian-influenza-bird-flu/bangladesh-and-india-alert-who-about-new-h5n1-infections
Scripps News Group. (2025, July 2). Waffle House ends egg surcharge as bird flu-induced shortage subsides. KATC News. https://www.katc.com/business/company-news/waffle-house-ends-egg-surcharge-as-bird-flu-induced-shortage-subsides
The Economic times. (2025, July 13). H5N1 avian influenza detected in Odisha’s Puri dist; govt culls over 6,700 birds. The Economic Times; Economic Times. https://economictimes.indiatimes.com/news/india/h5n1-avian-influenza-detected-in-odishas-puri-dist-govt-culls-over-6700-birds/articleshow/122419971.cms?from=mdr
Van Beusekom, M. (2025, July 17). Center for Infectious Disease Research and Policy. CIDRAP. https://www.cidrap.umn.edu/avian-influenza-bird-flu/avian-flu-exacts-heavy-financial-toll-dairy-industry-report-says